EP3951367A1 - Optical process sensor, measuring head, measuring system comprising the two and method for calibrating and / or validating - Google Patents

Abstract

The invention discloses an optical process sensor (1), in particular a spectrometer, for measuring at least one measured variable of a medium in a container, comprising: a housing (2); a light source (3) in the housing (2) for emitting transmitted light (5); a light receiver (4) in the housing (2) for receiving received light (6); and a first optical-mechanical interface (10) comprising a first optical section (11) protruding from the housing (2) with a first path (12) and a first light guide (13), the first light guide (13 ) is designed such that transmitted light (5) is guided via the first light line (13) from the light source (3) into the first path (12), and transmitted light (5) is decoupled from the housing (2), and with a second path (14) and a second light line (15), the second light line (15) being designed in such a way that received light (6) couples into the interior of the housing (2) and via the second light line (15) from the second path (14 ) to the light receiver (4), and a first mechanical section (21) designed as an integral part of the housing (2). The invention also discloses a measuring head (51), an optical measuring system (100) comprising the two and a procedure.

Description

The invention relates to an optical process sensor, a measuring head that goes with it, a measuring system comprising the two, and a method for calibrating and/or validating.

Within the meaning of this application, “process sensors” refer to sensors that are used to optimize, analyze and control manufacturing processes at the field level, such as in the chemical or pharmaceutical industry. These process sensors enable qualitative and quantitative analysis during the running process. For example, physical or chemical parameters are recorded in real time and used for system control or regulation.

the DE 20 2013 101 907 U1 explained that with such process sensors it is necessary from time to time to clean the sample chamber or the sensor, for which purpose short-wave radiation such as gamma radiation or high temperatures can be used in particular. This entails considerable risks for the comparatively sensitive optics of the measuring probes; In particular, the aggressive radiation or the high temperatures can also destroy the optical part of the measuring probe, so that precautions must be taken to protect the sensitive optics from damage or even destruction when cleaning. The The DE 20 2013 101 907 U1 proposes that the part that comes into direct contact with the sample to be examined be made detachable so that it can be easily removed from the sensitive parts of the sensor during cleaning.

Optical sensors that are used, for example, in the food and pharmaceutical industries must be regularly validated to ensure that they function correctly. The properties to be checked here are regulated, among other things, in the Pharmacopoeia, USP (USA) and a corresponding counterpart in Europe. These are, for example, the wavelength accuracy, the photometric accuracy or linearity, the scattered light behavior and the resolving power with regard to the wavelength.

For the tests described above, test liquids and solid standards in the form of cuvettes or filter sets with the appropriate certificates are available for laboratory devices. The laboratory devices can easily be validated with these standards. To do this, the cuvette standards or the filters are placed in the beam path of the instrument to be validated.

This procedure is not possible with process sensors because the optical beam path is not accessible, since it is protected from the harsh process environment in particular. Process sensors often work with measuring cells, which are connected to a decoupled measuring system via fiber optics with the light sources and receivers. To validate the measuring system, the light guides are removed from the corresponding measuring cell and connected to a cuvette holder.

There are versions with a slit in the beam path into which mechanically adapted filters, mostly solid-state filters, can be placed in the beam path. These solutions have the disadvantage that it is often not possible to use standards with certified values.

The object of the invention is to validate and calibrate process sensors in a simple manner.

The object is achieved by an optical process sensor for measuring at least one measured variable of a medium in a container, comprising: a housing; a light source in the housing for emitting transmission light; a light receiver in the housing for receiving received light; and a first optical-mechanical interface, comprising: a first optical section, which protrudes from the housing, with a first path and a first light guide, wherein the first light guide is configured such that transmitted light via the first light guide from the light source into the first Path is guided, and transmitted light is coupled out of the housing, and with a second path and a second light line, the second light line being designed in such a way that received light is coupled into the interior of the housing and is guided from the second path to the light receiver via the second light line , and a first mechanical portion configured as an integral part of the housing.

The advantages of the solution with the described optical sensor, especially in combination with a measuring head, which together form an optical measuring system, are discussed below.

One embodiment provides that the first and second light guide is designed as an optical waveguide.

One embodiment provides that the first and second path are designed as two separate rod-shaped, in particular cylindrical, continuations, which are connected to the housing in particular by screwing, gluing, welding or by frictional locking, with the first and second light guide inside the continuations is led.

One embodiment provides that the first and second path at the end area remote from the process sensor, in particular in each case, comprises an optical element, in particular a window and/or a lens, the optical element being transparent for the transmitted light and received light.

One embodiment provides that the sensor is designed as a spectrometer.

The object is further achieved by an optical process sensor which is designed to measure at least one measured variable of a medium in a container, the measuring head comprising: a housing which is designed to connect the sensor to the container; a second optical-mechanical interface, comprising a second optical section which is complementary to a first optical section.

In one configuration, the second optical section is designed as a recess in the housing.

The first optical section includes a third path that receives transmitted light and couples it into the interior of the housing.

In one configuration, the third path leads the transmitted light to a deflection element.

The first optical section includes a fourth path, which receives transmitted light, guides it through an area through which a medium flows, the transmitted light being converted into received light by the medium, and couples received light out of the housing.

The second opto-mechanical interface comprises a second mechanical section which is complementary to a first mechanical section and is designed as an integral part of the housing.

One embodiment provides that the measuring head includes a deflection element in the housing, which deflects the transmitted light or received light from the third path into the fourth path or vice versa.

In one embodiment, the area through which the medium flows is designed as a further recess in the housing.

In one embodiment, the measuring head thus comprises an optical process sensor which is designed to measure at least one measured variable of a medium in a container, the measuring head comprising: a housing which is designed to connect the sensor to the container; a second optical-mechanical interface, comprising a second optical section which is complementary to a first optical section and which is designed as a recess is configured in the housing, a third path, which receives transmitted light, couples it into the interior of the housing and leads to a deflection element, and a fourth path, which receives transmitted light from the deflection element, through an area through which the medium flows, the transmitted light being converted by the medium into received light and decouples received light from the housing, and a second mechanical section, which is complementary to a first mechanical section and is designed as an integral part of the housing, the deflection element, which is arranged in the housing, and the area through which the medium flows, which is a further recess of the housing is designed.

In one configuration, the measuring head comprises an optical process sensor, which is designed to measure at least one measured variable of a medium in a container, the measuring head comprising: a housing, which is designed to connect the sensor to the container; a second opto-mechanical interface, comprising a second optical section, which is complementary to a first optical section and is designed as a recess in the housing, couples a third path, which receives transmitted light, into the interior of the housing, through an area through which the medium flows, wherein the transmitted light is converted by the medium into received light, and leads received light to a deflection element, and a fourth path that receives received light from the deflection element and decouples it from the housing, and a second mechanical section that is complementary to a first mechanical section and that acts as an integral Part of the housing is configured, the deflection element, which is arranged in the housing, and the area through which the medium flows, which is configured as a further recess of the housing.

The medium-flow path can thus be arranged in the third or in the fourth path.

The use of an opto-mechanical interface on the sensor and measuring head makes it possible to decouple different types of measuring heads such as immersion probes or flow cells from process sensors. This allows the measuring head to remain in the process and keeps it closed for the further validation process of the sensor.

The removed sensor with the opto-mechanical interface can now be used for the validation process. By replacing the measuring head on the sensor with a validation adapter (which is regarded as a special configuration of a measuring head) for accommodating certified cuvettes or filters, the sensor can be checked easily.

As with a laboratory spectrometer, the full validation of the process sensor is made possible with this validation device and the option of being able to use certified standards (cuvettes, filters).

One embodiment provides that the deflection element deflects the transmitted light by 180°.

One embodiment provides that the deflection element is designed as a prism.

One embodiment provides that the third and fourth path are designed as two separate rod-shaped, in particular cylindrical, recesses.

One embodiment provides that the third and fourth path, in particular each, includes an optical element, in particular a window and/or a lens, the optical element being transparent for the transmitted light and received light.

One embodiment provides that the third or fourth path includes a window to the area through which the medium flows, the window being transparent for the transmitted light and received light.

One embodiment provides that the measuring head is designed as an immersion probe.

One embodiment provides that the measuring head is designed as a flow probe. One embodiment provides that the measuring head is designed as a calibration and validation device.

Here you can see the special advantages of the optical-mechanical interface. Different measuring heads can be easily exchanged. The "actual" measuring head, e.g. a flow probe or immersion probe, remains in the process. After removing the sensor, a calibration and validation device is placed on the same opto-mechanical interface. The optical path is the same as in the process and the sensor can be calibrated.

One embodiment provides that the calibration and validation device includes a cuvette holder with a holder for a cuvette, the holder forming the area through which the medium flows.

One embodiment provides that the cuvette holder includes a solid standard.

One embodiment provides that the calibration and validation device includes a cuvette changer.

One embodiment provides that the calibration and validation device includes a filter wheel or filter changer.

This also enables the process sensors to be checked automatically using a corresponding exchange unit (e.g. filter wheel, cell changer).

The object is further achieved by an optical measuring system comprising an optical process sensor as described above and a measuring head as described above, the second optical section accommodating the first optical section to form an optical connection with a light path from the light source, first light line, first path, third To enable path, deflection element, fourth path, second path, second light line and light receiver, and a mechanical connection of the optical process sensor and measuring head via the first mechanical section and second mechanical section.

One embodiment provides that the mechanical connection is detachable, in particular the first mechanical section and the second mechanical section are designed such that there is a screw connection, in particular the first mechanical section and the second mechanical section include bores and/or threads for screws.

The object is further achieved by a method for calibrating and/or validating an optical process sensor, comprising the steps of: removing the sensor from a measuring head, which is designed as a flow probe or immersion probe; Attaching the sensor to a measuring head which is designed as a calibration and validation device; calibrating and validating the sensor using the calibration and validation device; removing the sensor from the calibration and validation device; and reattaching the sensor to the flow probe or submersible probe.

Fig. 1a, b

zeigen den beanspruchten optischen Prozesssensor im Querschnitt und einer Seitenansicht.

Fig. 2a-d

zeigen das beanspruchten Messsystem in einer Ausgestaltung (Tauchsonde).

Fig. 3a-d

zeigen das beanspruchten Messsystem in einer Ausgestaltung (Durchflusssonde).

Fig. 4a-e

zeigen das beanspruchten Messsystem in einer Ausgestaltung (Küvettenhalter).

Fig. 5

zeigt das beanspruchten Messsystem in einer Ausgestaltung (LED-Sensor)

Fig. 6a-c

zeigen den Küvettenhalter mit und ohne Festkörperstandard.

This is explained in more detail with reference to the following figures.

Fig. 1a, b

show the claimed optical process sensor in cross section and a side view.

Fig. 2a-d

show the claimed measuring system in one embodiment (immersion probe).

Fig. 3a-d

show the claimed measurement system in one embodiment (flow probe).

Fig. 4a-e

show the claimed measurement system in one embodiment (cuvette holder).

figure 5

shows the claimed measuring system in one embodiment (LED sensor)

Fig. 6a-c

show the cuvette holder with and without solid state standard.

In the figures, the same features are marked with the same reference symbols.

The claimed measuring system in its entirety has the reference number 100 and is, for example, in Fig. 2d shown. First, the individual components will be discussed, namely a process sensor 1 and a measuring head 51.

Figures 1a and 1b show the sensor 1 with the housing 2. The sensor is an optical sensor. This is, for example, a spectrometer with a light source 3 and a light receiver 4. The light source 3 emits transmitted light 5 and the light receiver 4 receives received light 6, which is produced by converting the transmitted light 5 on the medium to be measured (see below). The light 5 emitted by the light source 3 is thus converted by the medium, for example absorbed, scattered or fluorescent light is produced. This converted light 6 is picked up by the receiver 4 and converted into an electrical signal.

The sensor 1 comprises a first opto-mechanical interface 10, which consists of an optical section 11 and a mechanical section 21.

The mechanical section 21 is used to connect the sensor 1 to the measuring head 51, for example by screwing, with appropriate devices, ie holes, threads or bores 22 and 72 being present. The mechanical section 21 is an integral part of the housing 2.

The optical section 11 projects out of the housing 2 . This comprises a first path 12 and a first light guide 13 , for example an optical waveguide or a free beam guide, which introduces the transmitted light 5 from the light source 3 into the first path 12 and then decouples the transmitted light 5 from the housing 2 . This also includes a second path 14 and a second light line 15, such as an optical waveguide or a free beam guide, which couples the received light 6 into the interior of the housing 2 and guides it from the second path 14 to the light receiver 4 via the second light line 15. The paths 12, 14 are separate, cylindrical continuations, which are screwed to the housing 2, for example, with the optical waveguides 13, 15 being routed inside.

Figure 2a shows the measuring head 51 in cross section, Figure 2c in a side view. Figure 2b shows sensor 1, right next to it Figure 2a . Fig. 2d shows the measuring system 100 in the assembly of sensor 1 and head 51.

The measuring head 51 includes a second opto-mechanical interface 60, which consists of an optical section 61 and a mechanical section 71.

The mechanical section 71 is used to connect the measuring head 51 to the sensor 1, for example by screwing, with corresponding devices, ie for example holes, Threads or holes 22 and 72 are present. The mechanical section 71 is an integral part of the housing 52.

In addition, the housing 52 is designed for connection to a container. For this purpose, the housing 52 comprises corresponding connection means. The connection means can be designed as a welded or flanged connection, e.g. made of stainless steel. However, other configurations are possible. The measuring medium to be measured is located in the container. The container can be a container, boiler, pipe, pipeline or the like.

The second opto-mechanical interface 60 initially comprises a second optical section 61 which is complementary to a first optical section 11 and is designed as a recess in the housing 52 . This includes a third path 62 which receives the transmitted light 5, couples it into the interior of the housing 52 and leads to a deflection element 67. This further comprises a fourth path 64, which receives the transmitted light 5 from the deflection element 67, leads it through an area 68 through which the medium flows, with the transmitted light 5 being converted into received light 6 by the medium in the area 68 through which the medium flows, and finally the received light 6 is decoupled from the housing 52 again .

The deflection element 67 deflects the transmitted light 5 by 180° and is designed as a prism.

The third and fourth paths 62, 64 are designed as two separate rod-shaped, in particular cylindrical, recesses. The third and fourth pathways 62, 64 are designed to complement the first and second pathways 12, 14 so that the continuations fit snugly into the recesses. If the sensor 1 and the head 51 are assembled and mechanically fixed via the mechanical sections 11, 61, the two optical sections 11, 51 are positioned in such a way that the transmitted light 5 or the received light 6 is guided ideally from the sensor 1 into the head 51 or vice versa will. There are designs with lenses 16 (as shown) or windows.

The transmitted light 5 exits the measuring head 51 for a short time, passes through the area 68 through which the medium flows and then re-enters the housing 52 at the appropriate point. Transparent windows 66 separate the interior from the media (for clarity, the reference number indicates only the left window). The path 68 through which the medium flows can be arranged in the third or in the fourth path 62 , 64 .

the Figures 2a-2d show the configuration of the measuring head 51 as an immersion probe. In this case, the measuring head 51 is located in the medium to be measured and also remains there. However, the measuring head 51 can also be removed from the process and from the sensor, for example for maintenance purposes such as changing seals.

Figures 3a-3d are systematically constructed in the same way, with the measuring head 51 being designed as a flow probe. Medium flows through an inlet 69a and leaves the flow probe again at the outlet 69b. Inside is the area 68 through which the medium flows.

If a validation or calibration of the sensor 1 is now necessary, it can simply be removed from the measuring head 51 in the process (e.g. designed as a flow probe) by loosening the screw connection.

The measuring head 51 can be designed as a calibration and validation device.

This is what they show Fig. 4a-e , where the Fig. 4a-d initially have the same systematic structure as the Fig. 2a-e .

The sensor 1 is thus removed and the measuring head 51 in the configuration as a calibration and validation device, which also has a second opto-mechanical interface 60, is attached to the sensor 1.

A configuration of the calibration and validation device is a cuvette holder. The holder 80, into which a cuvette 81 is placed, is located at the area 68 through which the medium flows. The cuvette 81 can be configured as a standard, for example as a solid body standard. Shows the assembled condition Figure 4d , whereby the cuvette holder is not fully assembled.

Figure 4e shows the configuration as a cuvette holder with an inserted sensor, only the first optical section 11 being visible. Some components are drawn transparently to show the assembly, especially the optical sections 11, 61. The sensor 1 can be calibrated, validated and, if necessary, adjusted by means of the cuvette holder 51 .

The calibration and validation device can also be designed as a cuvette changer, filter wheel or filter changer. Different absorptions can be set on the filter wheel so that different situations can be simulated by turning it.

Finally, the sensor 1 is removed from the calibration and validation device and can be reconnected to the other measuring head, for example the immersion probe or the flow probe.

Reference List

1

process sensor

2

housing from 1

3

light source

4

light receiver

5

transmission light

6

receiving light

10

first optical-mechanical interface

11

first optical section

12

first path

13

first light line

14

second path

15

second light line

16

lens

21

first mechanical section

22

Hole/thread for screws

51

measuring head

52

Case of 51

60

second optical-mechanical interface

61

second optical section

62

third path

64

fourth path

66

window

67

deflection element

68

medium-flow area

69a

flow clean

69b

flow out

71

second mechanical section

72

Hole/thread for screws

80

bracket

81

cuvette

100

measuring system

Claims (10)

Optical process sensor (1), in particular a spectrometer, for measuring at least one measured variable of a medium in a container, comprising - a housing (2), - a light source (3) in the housing (2) for emitting transmitted light (5), - A light receiver (4) in the housing (2) for receiving received light (6), and - a first opto-mechanical interface (10) comprising ▪ a first optical section (11) protruding from the housing (2), ∘ with a first path (12) and a first light line (13), the first light line (13) being designed such that transmitted light (5) via the first light line (13) from the light source (3) into the first path ( 12) is guided, and emitted light (5) decouples from the housing (2), and ∘ with a second path (14) and a second light line (15), the second light line (15) being designed in such a way that received light (6) couples into the interior of the housing (2) and via the second light line (15) from second path (14) to the light receiver (4), and ▪ a first mechanical section (21) which is designed as an integral part of the housing (2). Measuring head (51) for an optical process sensor (1), which is designed to measure at least one measured variable of a medium in a container, the measuring head (51) comprising - a housing (52) which is designed to connect the sensor (1) to the container, - a second opto-mechanical interface (60) comprising ▪ a second optical section (61) complementary to a first optical section (11), ∘ a third path (62) which receives the transmitted light (5) and couples it into the interior of the housing (52), and ∘ a fourth path (64), which receives transmitted light (5), through an area (68) through which medium flows, the transmitted light (5) being converted into received light (6) by the medium, and received light (6) from the housing ( 52) decouples, and ▪ a second mechanical section (71), complementary to a first mechanical section (21), which is designed as an integral part of the housing (52), Measuring head (51) according to one of the preceding claims,
wherein the measuring head (51) is designed as an immersion probe. Measuring head (51) according to one of the preceding claims,
wherein the measuring head (51) is designed as a flow probe. Measuring head (51) according to one of the preceding claims,
wherein the measuring head is designed as a calibration and validation device. Measuring head (51) according to claim 5,
wherein the calibration and validation device comprises a cuvette holder with a holder for a cuvette, the holder forming the area through which the medium flows. Measuring head (51) according to claim 5,
wherein the calibration and validation device comprises a cuvette changer, filter wheel or filter changer. Optical measuring system (100) comprising an optical process sensor (1) according to one of the preceding claims and a measuring head (51) according to one of the preceding claims, wherein the second optical section (61) accommodates the first optical section (11) to enable an optical connection with a light path of light source, first light guide, first path, third path, deflection element, fourth path, second path, second light guide and light receiver, and a mechanical connection of optical process sensor (1) and measuring head (51) via the first mechanical section (21) and second mechanical section (71) enables. Optical measuring system (100) according to the preceding claim, the mechanical connection being detachable, in particular the first mechanical section (21) and the second mechanical section (71) are designed in such a way that there is a screw connection, in particular, the first mechanical section (21) and the second mechanical section (71) comprise bores and/or threads for screws. Method for calibrating and/or validating an optical process sensor (1), comprising the steps - Removing the sensor (1) from a measuring head, which is designed as a flow probe or immersion probe; - Attaching the sensor (1) to a measuring head which is designed as a calibration and validation device; - Calibrating and validating the sensor (1) by means of the calibration and validation device; - Removal of the sensor (1) from the calibration and validation device; and - Reattach the sensor (1) to the flow probe or submersible probe.

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